Curable aqueous compositions

ABSTRACT

A curable composition useful as a thermosetting binder, comprising a polycarboxy polymer or copolymer, a glycerol derivative, and, optionally, a phosphorous containing compound.

The present invention relates to curable compositions that impartimproved flexibility to substrates when cured thereon, to methods of usethereof as binders for fibrous substrates and composites, and to theproducts produced by those methods. More particularly, the presentinvention relates to aqueous thermosetting binder compositionscomprising one or more carboxy (co)polymer, one or more glycerolderivative, chosen from the group consisting of ethoxylated andpropoxylated glycerol having weight average molecular weight greaterthan 1000, and the use thereof as binders for heat-resistant fibers andnonwovens.

Fibrous substrates such as heat resistant nonwovens may comprise mattedfibers bonded together by a cured thermosetting resinous material. Inmaking fiberglass insulation, for example, drawn glass fibers of randomlengths are randomly deposited as a mat and, while still hot fromdrawing, are sprayed with an aqueous binder which is dried and cured.Due to their excellent cost/performance ratio, the thermosettingfiberglass binder resins of choice in the past have beenphenol/formaldehyde resins.

Phenol/formaldehyde resins can be economically produced, and can beextended with urea prior to use as a binder in many applications. Overthe past several decades however, increasingly stringent Federalregulations, increased awareness of the environmental risks posed byphenol/formaldehyde resins such as the declaration by the World HealthOrganization that formaldehyde is a human carcinogen have led industryto minimize formaldehyde emissions and to investigate formaldehyde freebinder systems.

Existing commercial formaldehyde-free binders contain a carboxylic acidpolymer and a polyol that esterify and form a thermoset when heat cured.Commercial binders have typically been designed to afford a binder thatwhen cured is substantially rigid. For example, in fiberglass insulationbinders, the cured binders must allow the insulation to be compressed,but have rigidity that allows the compressed insulation to recoversubstantially to its original shape once compressive forces are removed.This allows, for example, the insulation to be shipped in a rolled,compressed state and unrolled before installation to release thecompression, and allow a fluffy, heat-insulating mat to be installed.

However, for other applications, the rigid binders of the type describedabove are undesirable. For example, in thin fiberglass or polyester matsthat are to be used in roofing, the mat must be held together with abinder that allows the mat to flex substantially after the binder iscured, to allow the mat to be processed further (e.g., to convert matinto roofing material), and allow the end product containing the mat toflex well in use. For example, in roofing mat, the end roofing productmay be impregnated or layered with asphaltic materials, and theresultant roofing product must retain flexibility to allow it to conformto the roof (e.g., bend over peaks and into valleys), and to allow theroofing material to expand and contract with temperature fluctuations,without the mat itself fracturing because it is too brittle and lacksflexibility.

Other applications where curable, formaldehyde-free binders are“flexible” in this regard include paper, cellulosics, polyester andglass veil. Such substrates are used in a variety of applications,including flooring underlayments, filtration media, and buildingproducts.

Commercial formaldehyde-free binders have been blended with otherpolymers, as described, for example, in International Publication No. WO2006/063802 A2. However, the dispersions described therein are high Tgsystems that would be unsuitable for applications requiring bothflexibility and strength of the product. Moreover, the systems based onamine-containing polyols are susceptible to undesirable high temperaturediscoloration. On the other hand, systems based on known amine-freepolyols, such as glycerol or sorbitol, show better high temperaturecolor stability properties but insufficient flexibility and strength.Thus, there is a need for new formaldehyde-free binders for making aheat-resistant nonwoven fabric with improved flexibility.

This invention is a formaldehyde-free binder that retains flexibilityafter cure.

Accordingly, the present inventors have endeavored to provide aqueousthermosetting binders for fibrous substrates and composites that enablehigher levels of flexibility than is provided by the current technology,at a cost that can compete with phenol/formaldehyde resins, and withoutposing the environmental hazards of formaldehydes.

The present invention provides curable aqueous compositions comprising:(a) at least one polycarboxy polymer or copolymer comprising at leasttwo carboxylic acid groups, anhydride groups, or salts thereof; (b) atleast one glycerol derivative having weight average molecular weightgreater than 1000 and comprising at least three hydroxyl groups, thesaid glycerol derivative chosen from the group consisting of ethoxylatedand propoxylated glycerol of formula I

in which u, v, w, x, y, and z independently of one another are 0-50,with the proviso that the total sum of u, v, w, x, y, and z provides aweight average molecular weight of the glycerol derivative greater than1000;wherein the ratio of the number of equivalents of said carboxylic acidgroups, anhydride groups, or salts thereof to the number of equivalentsof said hydroxyl groups is from 1/0.001 to 1/1.

This invention also is a method for treating substrates with such acomposition, which includes forming a curable aqueous compositioncomprising admixing the components of the invention with water or one ormore aqueous solvent; contacting said substrate with said curableaqueous composition or, alternatively, applying said curable aqueouscomposition to said substrate; and heating said curable aqueouscomposition at a temperature of from 100° C. to 400° C. The inventionalso provides a fibrous article, non-woven article or composite preparedby the method for treating substrates with the composition, as describedabove.

Preferably, the polycarboxy (co)polymer (a) of the curable aqueouscomposition is an addition copolymer of (meth)acrylic acid with one ormore monomers selected from the group consisting of C₁-C₁₂ alkyl(meth)acrylates, C₁-C₁₂ hydroxyalkyl (meth)acrylates, vinyl esters ofC₂-C₁₂ carboxylic acids, butadiene, vinyl acetate, alkyl maleates andalkyl fumarates.

In another embodiment, the aqueous curable composition further comprisesat least one polyether compound of the general formulaHO—(CR₂—CR₂—O)_(n)—H, in which R independently at each occurrence is Hor C₁₋₄ alkyl, and n is between 5-100,000.

In another embodiment, the aqueous curable composition further comprisesat least one phosphorous-containing compound.

In another embodiment, the aqueous curable composition further comprisesat least one emulsion polymer including, as polymerized units, at leastone ethylenically unsaturated nonionic acrylic monomer.

In another embodiment, the aqueous curable composition further comprisesone or more polyols selected from the group consisting of glycerol,ethyleneglycol, diethyleneglycol, triethyleneglycol, hexanediol,trimethylolpropane, pentaerythritol, sorbitol, sucrose, glucose,triethanolamine and diethanolamine at a level of from 0 to 10% by weighton total formulation solids.

In yet another embodiment, the polycarboxy (co)polymer (a) of theaqueous curable composition is polyacrylic acid.

All ranges recited are inclusive and combinable. For example, an averageparticle size of 1.3 μm or more, for example, 1.5 μm or more, which maybe 4.5 μm or less, or 4.0 μm or less, will include ranges of 1.3 μm ormore to 4.5 μm or less, 1.5 μm or more to 4.5 μm or less, 1.5 μm or moreto 4.3 μm or less, and 1.3 μm or more to 4.3 μm or less.

As used herein, the term “(meth)acrylate” means acrylate, methacrylate,and mixtures thereof and the term “(meth)acrylic” used herein meansacrylic, methacrylic, and mixtures thereof.

All phrases comprising parenthesis denote either or both of the includedparenthetical matter and its absence. For example, the phrase“(co)polymer” includes, in the alternative, polymer, copolymer andmixtures thereof.

As used herein, unless otherwise indicated, the phrase “copolymer”includes, independently, copolymers, terpolymers, block copolymers,segmented copolymers, graft copolymers, and any mixture or combinationthereof.

As used herein, unless otherwise stated, the term “polycarboxy(co)polymer” is an oligomer, co-oligomer, polymer or copolymer with atleast two carboxylic acid functional groups, anhydride groups, or saltsthereof.

As used herein, the phrase “addition polymer” refers to any (co)polymerthat comprises ethylenically unsaturated monomers as (co)polymerizedunits, such as poly(acrylic acid) (pAA).

As used herein, the phrase “aqueous” or “aqueous solvent” includes waterand mixtures comprising water and one or more water-miscible solvent.

As used herein, the phrase “based on the total weight of binder solids”or “based on total binder solids” refers to weight amounts in comparisonto the total amount of polycarboxy (co)polymers (a), glycerolderivatives (b), and other polyols.

As used herein, the phrase “formaldehyde-free composition” refers tocompositions substantially free from added formaldehyde, and which donot liberate substantial formaldehyde as a result of drying and/orcuring.

As used herein, the phrase “gradual addition” refers to polymerizationin which monomers are fed into a reaction vessel over time.

As used herein, the phrase “heat-resistant fibers” means fibers whichare substantially unaffected by exposure to temperatures of from 125° C.to 400° C. during processing.

As used herein, unless otherwise indicated, the phrase “molecularweight” refers to the weight average molecular weight of a polymer asmeasured by gel permeation chromatography (GPC) against a polyacrylicacid standard.

As used herein, the phrase “polybasic” means having at least tworeactive acid functional groups or salts or anhydrides thereof (see e.g.Hawley's Condensed Chemical Dictionary, 14^(th) Ed., 2002, John Wileyand Sons, Inc.).

As used herein, the phrases “polyol” and “polyhydroxy” refer to organiccompounds or structural portions of organic compounds containing two ormore hydroxy groups. As such, the term “polyol” can include the glycerolderivative (b) of the aqueous curable composition.

As used herein, the phrase “wt. %” stands for weight percent.

The formaldehyde-free curable compositions contain one or morepolycarboxy (co)polymer (a). The polycarboxy (co)polymer must besufficiently nonvolatile that it will substantially remain available forreaction with the polyol in the composition during heating and curingoperations. The polycarboxy (co)polymer may be one or more polymericpolycarboxy (co)polymer, one or more low molecular weight polycarboxy(co)polymer, or mixtures thereof.

The one or more polymeric polycarboxy (co)polymer may be chosen from,for example, polyesters containing at least two carboxylic acid groups,addition (co)polymers or oligomers containing at least two copolymerizedcarboxylic acid-functional monomers and oligomers of polybasic acids ortheir salts or anhydrides. Preferably, the one or more polymericpolycarboxy (co)polymer is chosen from addition (co)polymers formed fromat least one ethylenically unsaturated monomer, most preferably polymersand copolymers of (meth)acrylic acid. The addition (co)polymers may bein the form of solutions of the addition (co)polymer in an aqueousmedium such as, for example, an alkali-soluble resin which has beensolubilized in a basic medium.

Suitable addition (co)polymers contain at least two carboxylic acidgroups, anhydride groups, or salts thereof formed from the additionpolymerization of one or more ethylenically unsaturated carboxylicacids, anhydrides and salts thereof and, optionally, one or morecomonomers. Ethylenically unsaturated carboxylic acids or anhydrides mayinclude, for example, methacrylic acid, acrylic acid, crotonic acid,fumaric acid, maleic acid, 2-methyl maleic acid, itaconic acid,citraconic acid, mesaconic acid, cyclohexanedicarboxylic acid, 2-methylitaconic acid, α-methylene glutaric acid, monoalkyl maleates, andmonoalkyl fumarates, and salts thereof; ethylenically unsaturatedanhydrides, such as, for example, maleic anhydride, itaconic anhydride,acrylic anhydride, and methacrylic anhydride, and salts thereof. Thepreferred monomers that may include carboxylic acid groups, anhydridegroups, or salts are (meth)acrylic acid and maleic acid, and saltsthereof, and maleic anhydride. The monomers including carboxylic acidgroups, anhydride groups, or salts are used at a level of from 1 wt. %or more, based on the weight of the polymer, or 10 wt. % or more, or, 25wt. % or more, preferably 30 wt. % or more, or, more preferably 75 wt. %or more, or, even more preferably 85 wt. % or more, and up to 100 wt. %,for example, up to 99 wt. %, or up to 90 wt. %. Suitable ethylenicallyunsaturated comonomers may include one or more acrylic ester monomersincluding methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexylacrylate, decyl acrylate, methyl methacrylate, butyl methacrylate, andisodecyl methacrylate; hydroxyl group containing monomers, such ashydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxypropylmethacrylate and allyloxy functional hydroxyl group-containing monomers;acrylamide or substituted acrylamides, such as t-butylacrylamide;styrene or substituted styrenes; butadiene; vinyl acetate or other vinylesters; acrylonitrile or methacrylonitrile; and the like. Preferablecomonomers include one or more ethylenically unsaturated monomer havinga solubility of less than 2 g/100 g of water at 25° C., one or moreallyloxy functional hydroxyl group-containing monomers; one or morephosphorous-containing comonomers, such as vinyl phosphonic acid,phosphoalkyl (meth)acrylates, or salts thereof; or one or more strongacid functional monomers, such as vinyl sulfonic acid monomers, andtheir salts; or mixtures of any of such comonomers.

The one or more preferred addition comonomers having a solubility ofless than 2 g/100 g of water at 25° C. may be chosen from ethyl(meth)acrylate, methyl methacrylate, butyl (meth)acrylate, styrene,mono-alkyl (meth)acrylamide, di-alkyl (meth)acrylamide and t-alkylneopentyl alkyl acrylamides. Such comonomers may be included in theaddition monomer mixture in the amount of 3 or more wt. %, or 10 or morewt. %, and as much as 25 wt. % or less, or 20 wt. % or less, or 15 wt. %or less, based on the total weight of monomers used to make the additioncopolymer.

The one or more preferred allyloxy functional hydroxyl group-containingmonomers may be chosen from hydroxyl group-including monomers of FormulaI,

CH2=C(R1)CH(R2)OR3  (I)

wherein R1 and R2 are independently selected from hydrogen, methyl, and—CH₂OH; and R3 is selected from hydrogen, —CH2CH(CH3)OH, —CH2CH2OH,C(CH2OH)2—C2H5, and (C3-C12) polyol residues; or of Formula II,

wherein R is selected from CH3, Cl, Br, and C6H5; and R1 is selectedfrom H, OH, CH2OH, CH(CH3)OH, glycidyl, CH(OH)CH2OH, and (C3-C12)polyolresidues. Such allyloxy functional hydroxyl-group containing monomersmay be included in the addition monomer mixture at a level of up to 99wt. %, or up to 70 wt. %, preferably, up to 30 wt. %, based on the totalweight of the monomer mixture, and can be used in amounts of 1 wt. % ormore, or 10 wt. % or more, based on the total weight of the monomermixture. The most preferred monomers of Formula I and Formula II areallyl alcohol and 3-allyloxy-1,2-propanediol.

The one or more polycarboxy (co)polymer addition (co)polymer maysuitably have a weight average molecular weight of 1000 or more, or5,000 or more, or advantageously 10,000 or more, and the molecularweight may range as high as to 250,000, or, more preferably, as high as100,000. A molecular weight range of 20,000 to 250,000 is preferred, andmost preferably is about 75,000.

In another embodiment of the present invention the polycarboxy(co)polymer addition (co)polymers may be oligomers or co-oligomers ofethylenically-unsaturated carboxylic acids prepared by free radicaladdition polymerization, having a number average molecular weight ofbetween 300 and 900.

The one or more polycarboxy (co)polymer addition (co)polymer maypreferably be prepared by solution polymerization techniques forpolymerizing ethylenically-unsaturated monomers which are well known inthe art.

The polymerization reaction to prepare the copolymer component can beinitiated by various methods known in the art, such as, preferably, byusing the thermal decomposition of one or more initiators, for example,by using an oxidation-reduction reaction (“redox reaction”) to generatefree radicals to effect the polymerization. Preferred thermal initiatorsmay comprise peracids, such as persulfates, perborates, and periodates.Redox initiator systems may contain at least one peroxide-containingcompound in combination with a redox co-initiator, for example, areductive sulfur compound such as a bisulfite, sulfite, thiosulfate,dithionite, or tetrathionate of alkali metals and ammonium compounds.Thus, it is possible to employ combinations of peroxodisulfates withalkali metal hydrogen sulfites or ammonium hydrogen sulfites, forexample, ammonium peroxydisulfate and ammonium disulfide. The ratio ofperoxide-containing compound to redox co-initiator is typically from30:1 to 0.05:1.

In the effective selection of one or more thermal initiators, thethermal decomposition temperature of the selected initiator shouldcorrespond to the one or more polymerization temperatures. Thus, if thereaction mixture is initially polymerized partly at the lower limit ofthe temperature range appropriate for polymerization, and is thenpolymerized to completion, at a higher temperature, it is expedient touse at least two different initiators which decompose at differenttemperatures, so that there is sufficient concentration of free radicalsavailable within each temperature range.

In combination with the initiators, it is possible to use, in addition,transition metal catalysts, such as salts of iron, cobalt, nickel,copper, vanadium, and manganese. Suitable salts include, for example,iron (II) sulfate, cobalt (II) chloride, nickel (II) sulfate, and copper(I) chloride. The reductive transition metal salt may be used in aconcentration of from 0.1 to 1,000 ppm, based on the monomers in thecurable composition.

Preferably, the addition (co)polymer may be polymerized in the presenceof one or more chain transfer agents to prepare (co)polymers of lowaverage molecular weight. Customary regulators may be used, for example,organic compounds containing SH groups, such as 2-mercaptoethanol,2-mercaptopropanol, mercaptoacetic acid or esters thereof,mercaptopropionic acid or esters thereof, tert-butylmercaptan,n-octylmercaptan, n-dodecylmercaptan, and tert-dodecylmercaptan; C₁-C₄aldehydes, such as acetaldehyde, propionaldehyde; hydroxylammoniumsalts, such as hydroxylammonium sulfate; formic acid; sodium bisulfiteor isopropanol. The addition (co)polymer may be formed in the presenceof a phosphorous-containing regulator, such as, for example,hypophosphorous acid and its salts, e.g. sodium hypophosphite, as isdisclosed in U.S. Pat. No. 5,294,686, so as to incorporate the optionalphosphorous-containing species in the polycarboxy (co)polymer molecule.The regulators are generally used in amounts of from 0 to 40 weightpercent, preferably from 0 to 15 weight percent, based on the weight ofthe monomers in the curable composition.

The addition (co)polymers can be prepared in water or in solvent/watermixtures such as, for example, i-propanol/water, tetrahydrofuran/water,and dioxane/water.

The preferred method of polymerization is by gradual addition solutionpolymerization in water. In this method, part, or all of theethylenically unsaturated (co)monomer or monomer mixture can be meteredinto the reactor. The manner in which the (co)monomers may be fed to areaction container or vessel may vary. No matter the method ofpolymerization, the preferred total feed time, i.e. the time required tofeed all of the reaction mixture into the reaction container, may range2 hours or less, more preferably, 1 hour or less.

In one embodiment of the method of polymerization, the composition ofthe monomer feeds remains substantially the same throughout thepolymerization process. Alternatively, to limit the gel content of anyaddition (co)polymerization product, the comonomer feed composition maybe adjusted during the duration of the raw material feeds. In yetanother embodiment, the method of polymerization, the (co)monomers ormixtures thereof may be fed by a semi-continuous feed. In the preferredmethods of polymerization of the addition (co)polymer, the reactioncontainer contains an initial charge of a reaction mixture comprising 10wt. % or more of the total amount of chain transfer agent used, and asingle constant feed of the remainder of the chain transfer agent is fedcontinuously from a monomer vessel into the reaction container.

To improve solubility in aqueous media, the carboxylic acid groups,anhydride groups, or salts thereof of the one or more addition(co)polymer may be neutralized with one or more fixed or volatile base.Preferably, the carboxylic acid groups, anhydride groups, or salts ofthe addition (co)polymer may be neutralized with a volatile base. By“volatile base” is meant herein one or more base which is substantiallyvolatile under the conditions of treatment of the substrate with thecurable composition. By “fixed” base is meant herein, a base which issubstantially non-volatile under the conditions of treatment of thesubstrate with the curable composition.

Use of volatile bases permits curing of the binder composition without astrong acid catalyst, where such curing is possible. Suitable volatilebases include, for example, ammonia or volatile lower alkyl amines.Suitable fixed bases include, for example, sodium hydroxide, potassiumhydroxide, sodium carbonate, and t-butylammonium hydroxide. The fixedbase is sufficiently nonvolatile that it will substantially remain inthe curable composition during heating and curing operation. Thevolatile base can be used in addition to the fixed base. Fixedmultivalent bases such as, for example, calcium carbonate, may tend todestabilize aqueous dispersions if the copolymer component is used inthe form of an aqueous dispersion, however, they can be used in minoramounts.

The amount of one or more base utilized may be such that the carboxylicacid groups, anhydride groups, or salts thereof of the addition(co)polymer are neutralized to an extent of less than 35%, or less than20%, or less than 5%, calculated on an equivalents basis. It ispreferred not to use any neutralizing base.

The curable aqueous composition comprises at least one glycerolderivative (b) having weight average molecular weight greater than 1000and comprising at least three hydroxyl groups, the said glycerolderivative chosen from the group consisting of ethoxylated andpropoxylated glycerol, formula I (below),

in which u, v, w, x, y, and z independently of one another are 0-50,with the proviso that the total sum of u, v, w, x, y, and z provides aweight average molecular weight of the glycerol derivative greater than1000. Preferably, the glycerol derivative has a weight average molecularweight of 1,000 to 7,500, more preferably from 1,500 to 5,000, and mostpreferably around 2,200, and is added at a level of 5-50% solids basedon total binder solids.

The glycerol derivative (b) must be sufficiently nonvolatile that itwill substantially remain available for reaction with the polycarboxy(co)polymer in the composition during heating and curing operations.

The ratio of the number of equivalents of carboxy, anhydride, or saltsthereof in the curable compositions, i.e. the one or more polycarboxy(co)polymer (a), to the total number of equivalents of hydroxyl in theglycerol derivative (b) is from about 1/0.001 to about 1/1, preferablyfrom 1/0.005 to 1/0.5. To avoid an excess of volatile organic compounds(VOC's) and insure formation of a good cure network, an excess ofequivalents of carboxy, anhydride, or salts thereof to the equivalentsof hydroxyl in the curable compositions is preferred. Thus, the ratio ofthe number of equivalents of carboxy, anhydride, or salts thereof to thenumber of equivalents of hydroxyl in the polyol can be 1/0.01 or less,but most preferably it is from about 1/0.01 to about 1/0.1.

Preferably, the curable aqueous composition also contains one or morephosphorous-containing accelerator which may be a compound such as thosedisclosed in U.S. Pat. No. 6,136,916. Preferably, the accelerator isselected from the group consisting of sodium hypophosphite, sodiumphosphite, or a mixture thereof. The phosphorous-containing acceleratorcan also be one or more (co)oligomer bearing phosphorous-containinggroups added to the curable compositions, for example, a (co)oligomer ofacrylic acid formed in the presence of sodium hypophosphite by additionpolymerization. Further, the one or more phosphorous-containingaccelerator may comprise part of the polycarboxy (co)polymer (a) as anoligomer or (co)polymer bearing phosphorous-containing groups such as,for example, addition (co)polymers of acrylic and/or maleic acids and,optionally, ethylenically unsaturated comonomers, e.g. those having asolubility of less than 2 g/100 g of water at 25° C., or combinationsthereof, formed in the presence of sodium hypophosphite; polymericpolycarboxy (co)polymer addition copolymers comprisingphosphorous-containing monomer residues such as, for example,copolymerized phosphoethyl methacrylate and like phosphonic acid esters,and their salts. The one or more phosphorous-containing accelerator maybe used at a level of from 0 wt. % to 40 wt. %, based on the combinedweight of the polycarboxy (co)polymer and the polyol. Thephosphorous-containing accelerators may be used in the amount of 0.1 wt.% or more, based on the total weight of binder solids, and up to 25 wt.%, or up to 20 wt. %, or, preferably, up to 15 wt. %, and, morepreferably, up to 12 wt. %. When the phosphorous-containing acceleratorcomprises part of an addition (co)polymer, the wt. % of thephosphorous-containing accelerator is based on/determined by wt. % ofhypophosphite, phosphinate or phosphonate charged to the reactor as afraction of the total batch solids.

Thus, a particularly advantageous embodiment provides a curablethermoset composition utilizing a polycarboxy copolymer of acrylic acidand ethyl acrylate (70:30 ratio) with a weight average molecular weightof about 75,000 in combination with an ethoxylated glycerol of 2200weight average molecular weight, optionally with one or more otherpolyols, such that the ratio of carboxy groups to —OH groups is1.0/0.014, and using 5% SHP as a phosphorous containing catalyst.

The curable composition may be prepared by admixing the one or morepolycarboxy (co)polymer, the one or more polyol, and, if desired, theone or more phosphorous-containing accelerator and any additionalingredients using conventional mixing techniques.

In one embodiment of the invention, the curable composition furthercontains at least one low molecular weight polybasic carboxylic acid,anhydride or salt thereof having a molecular weight of 1000 or less,preferably 500 or less, and most preferably 200 or less. Thus,optionally, one or more low molecular weight polybasic carboxylic acid,anhydride or salt thereof may be mixed with one or more glycerolderivative (b), under reactive conditions, prior to mixing with one ormore polycarboxy (co)polymer (a). Examples of suitable low molecularweight polybasic carboxylic acids and anhydrides include, for example,maleic acid, maleic anhydride, fumaric acid, succinic acid, succinicanhydride, sebacic acid, azelaic acid, adipic acid, citric acid,glutaric acid, tartaric acid, itaconic acid, trimellitic acid,hemimellitic acid, trimesic acid, tricarballylic acid,1,2,3,4-butanetetracarboxylic acid, pyromellitic acid, oligomers ofcarboxylic acid, and the like. As discussed above, in certainembodiments, the (co)polymer composition can include an accelerator. Theaccelerator may be present during this reaction, which can be an in-situreaction, or alternatively, the accelerator may be added to thecomposition after completion of this in-situ reaction and prior tomixing with the polycarboxy (co)polymer.

In another embodiment, the aqueous curable composition further comprisesat least one fatty alcohol mono-functional hydroxyl compound selectedfrom the group consisting of capryl alcohol, capric alcohol, laurylalcohol, cetyl alcohol, linoleyl alcohol, oleyl alcohol, myristylalcohol, montanyl alcohol, and myricyl alcohol.

In another embodiment, the aqueous curable composition further comprisesat least one glycol ether mono-functional hydroxyl compound selectedfrom the group consisting of ethylene glycol monomethyl ether, propyleneglycol monomethyl ether, diethylene glycol monomethyl ether, dipropyleneglycol, dipropylene glycol monomethyl ether, and ethylene glycol n-butylether.

In another embodiment, the aqueous curable composition further comprisesat least one strong acid such as sulfuric acid, nitric acid or sulfonicacids such as p-toluene sulfonic acid.

In another embodiment, the aqueous curable composition further comprisesat least one polysaccharide, selected from the group consisting ofstarch, cellulose, gums, alginates, pectin, gellan and modifications orderivatives thereof which are provided by etherification,esterification, acid hydrolysis, dextrinization, oxidation or enzymetreatment.

In another embodiment, the aqueous curable composition further comprisesurea.

In another embodiment, the aqueous curable composition further comprisesat least one water-soluble lignin selected from the group consisting ofsodium lignosulfonate, low-molecular weight maltodextrin, and soybeanprotein.

Water may be admixed with the remainder of the composition optionally atthe point of use, and not before, to minimize shipping weight. The totalsolids of the curable compositions of the present invention may range upto 100 wt. %, based on the total weight of the composition, as in withan anhydrous and solvent free or a dried binder composition, or up to 70wt. %, as is the case with solutions or dispersions, or up to 60 wt. %,or up to 50 wt. %; such total solids may range as low as 0.5 wt. % ormore, or 1 wt. % or more, or 3 wt. % or more, or 5 wt. % or more. Thetotal solids of the curable compositions may be selected to providecompositions having a suitable viscosity for various means of treatingsubstrates. For example, sprayable curable compositions may have a totalsolids of 5 wt. %. However, substrates may be dipped in or themselvescontacted with curable compositions having a total solids of 10 wt. % ormore. As used herein, the term “total solids” refers to the sum of thetotal amount of binder solids, plus any fillers or extenders.

In one embodiment of the invention, the curable binder composition isblended with an emulsion polymer including, as polymerized units, atleast one copolymerized ethylenically-unsaturated nonionic acrylicmonomer. “Emulsion polymer” or “emulsion (co)polymer” means a(co)polymer dispersed in an aqueous medium that has been prepared byemulsion polymerization techniques known in the art as is discussed indetail in D. C. Blackley, Emulsion Polymerization (Wiley, 1975) and alsoin H. Warson, The Applications of Synthetic Resin Emulsions, Chapter 2(Ernest Benn Ltd., London 1972). The emulsion polymer used in blendingmay be present in an amount of from 1% to 40%, preferably from 5% to15%, by weight based on the weight of the curable binder composition, ona solids basis.

The composition of this invention can contain, in addition, conventionaltreatment components such as, for example, emulsifiers; pigments;fillers or extenders; anti-migration aids; curing agents; coalescence;surfactants, particularly nonionic surfactants; spreading agents;mineral oil dust suppressing agents; biocides; plasticizers;organosilanes; anti-foaming agents such as dimethicones, silicone oilsand ethoxylated nonionics; corrosion inhibitors, particularly corrosioninhibitors effective at pH<4 such as thioureas, oxalates, and chromates;colorants; antistatic agents; lubricants; waxes; anti-oxidants; couplingagents such as silanes, particularly Silquest™ A-187 (manufactured by GESilicones—OSi Specialties, located in Wilton, Conn., USA); WetlinkSilanes from GE (e.g Wetlink 78), and Dynasylan™ silanes from Degussaparticularly, epoxy silanes such as, but not limited to, Dynasylan™GLYMO and GLYEO; and oligomeric silanes such as HYDROSIL™. Also,polymers not of the present invention; and waterproofing agents such assilicones and emulsion polymers, particularly hydrophobic emulsionpolymers containing, as copolymerized units, greater than 30% by weight,based on the weight of the emulsion polymer solids,ethylenically-unsaturated acrylic monomer containing a C5 or greateralkyl group.

The composition of this invention is preferably formaldehyde-free.“Formaldehyde-free” means that the composition is substantially freefrom formaldehyde, nor does it liberate substantial formaldehyde as aresult of drying and/or curing. To minimize the formaldehyde content ofthe (co)polymer composition it is preferred, when preparing a polymer ofthe present invention, to use polymerization adjuncts such as, forexample, initiators, reducing agents, chain transfer agents, biocides,surfactants, and the like, which are themselves free from formaldehyde,do not generate formaldehyde during the polymerization process, and donot generate or emit formaldehyde during the treatment of a substrate.Likewise, it is preferable that any formulation additives be similarlyformaldehyde free. “Substantially free from formaldehyde” means thatwhen low levels of formaldehyde are acceptable in the waterbornecomposition or when compelling reasons exist for using adjuncts whichgenerate or emit formaldehyde, substantially formaldehyde-freewaterborne compositions can be used.

The composition of this invention may be used for treating varioussubstrates. Such treatments can be commonly described as, for example,coating, sizing, saturating, bonding, combinations thereof, and thelike. Typical substrates include wood, including, for example, solidwood, wood particles, fibers, chips, flour, pulp, and flakes; metal;plastic; fibers such as polyester, glass fibers; woven and non-wovenfabrics; and the like and their composite fibers. The (co)polymercomposition can be applied to a substrate by conventional techniquessuch as, for example, air or airless spraying, padding, saturating, rollcoating, foam coating, curtain coating, beater deposition, coagulation,or the like.

In one embodiment of this invention, the composition can be used as abinder for heat-resistant non-woven fabrics such as, for example,non-wovens which contain heat-resistant fibers such as, for example,aramid fibers, ceramic fibers, metal fibers, carbon fibers, polyimidefibers, certain polyester fibers, rayon fibers, rock wool, and glassfibers. “Heat-resistant fibers” mean fibers which are substantiallyunaffected by exposure to temperatures above 125° C. Suitable nonwovenfabric substrates may comprise fibers that have been consolidated bypurely mechanical means such as, for example, by entanglement caused byneedle-punching, by an air-laid process, or by a wet-laid process; bychemical means, such as, for example, treatment with a polymeric binder;or by a combination of mechanical and chemical means before, during, orafter nonwoven fabric formation. Heat-resistant non-wovens can alsocontain fibers which are not in themselves heat-resistant such as, forexample, certain polyester fibers, rayon fibers, nylon fibers, andsuper-absorbent fibers, in so far as they do not materially adverselyaffect the performance of the substrate.

Non-woven fabrics incorporating a (co)polymer composition shouldsubstantially retain the properties contributed by the cured aqueouscomposition such as, for example, tensile strength, and notsubstantially detract from essential non-woven fabric characteristics.The cured composition should not be too rigid or brittle, or becomesticky under processing conditions.

The curable aqueous (co)polymer composition, after it is applied to asubstrate, is heated to effect drying and curing. The duration andtemperature of heating will affect the rate of drying, processability,handleability; and property development of the treated substrate. Heattreatment at from 120° C. to 400° C. for a period of time between from 3seconds to 15 minutes can be carried out; treatment at from 175° C. to225° C. is preferred. “Curing” means a chemical or morphological changewhich is sufficient to alter the properties of the (co)polymer such as,for example, via covalent chemical reaction, ionic interaction orclustering, improved adhesion to the substrate, phase transformation orinversion, hydrogen bonding, and the like. The drying and curingfunctions can be performed in two or more distinct steps, if desired.For example, the composition can be first heated at a temperature andfor a time sufficient to substantially dry but not to substantially curethe composition, and then heated for a second time at a highertemperature and/or for a longer period of time to effect curing. Such aprocedure, referred to as “B-staging,” can be used to providebinder-treated nonwoven, for example, in roll form, which can at a laterstage be cured, with or without forming or molding into a particularconfiguration, concurrent with the curing process.

The heat-resistant non-wovens can be used for applications such as, forexample, insulation batts or rolls to be used in ovens and in buildingconstruction, as reinforcing mats for roofing or flooring applications,as roving, as microglass-based substrates for printed circuit boards, asbattery separators, as filter stock, e.g. for air duct filters, as tapestock, as reinforcement scrim in cementitious and non-cementitiouscoatings for masonry, or as abrasives; wovens, nonwovens and compositesfor use as abrasives and stock or prepregs therefor, e.g. brake shoesand pads, clutch plates, or as sheets or panels, as in ceiling tiles;and mineral or glass fiber-containing heat-resistant nonwoven fabricsimpregnated with hot asphaltic compositions, for example, attemperatures of from 150° C. to 250° C. to make roofing shingles or rollroofing materials.

The non yellowing flexible binders of the invention are also useful forbonding wood chips, abrasive matts, decorative laminate paper,laminating adhesives, filtration paper, or cotton rag bonding forautomotive sound insulation.

As polycarboxy (co)polymers can be corrosive to certain types ofprocessing equipment, particularly those made from soft steel, certaintypes of corrosion control may preferably be practiced when handlingsolutions containing such polycarboxy (co)polymers. These practices caninclude, for example, pH control, reducing use of or eliminating strongacids, reducing use of phosphorous-containing accelerators and polymerscontaining them, and using materials such as stainless steel in theprocess equipment itself instead of more corrosive material.

The following non-limiting examples illustrate the curable aqueouscomposition and the use thereof as a binder for heat-resistantnonwovens.

EXAMPLES Example 1 Synthesis of Polycarboxy Solution (Co)PolymersExample 1A Solution Synthesis Polymer 1A

All solution samples were prepared by the same procedure. A 5-literround-bottom flask equipped with a paddle stirrer, thermocouple,nitrogen inlet, and reflux condenser was charged with a mixture of 1207grams of deionized water and heated to 72-74° C. At temperature, 20.6grams of 0.15% ferrous sulfate solution was added, followed by a 2minute hold. A monomer mix was prepared according to the recipe shown inTable 1. After hold, and at temperature, the monomer mix and a solutionof 16.08 grams of sodium persulfate in 236 grams of deionized water wasgradually added over 90 minutes and a solution of sodium metabisulfite(15.3 grams in 214 grams deionized water) was gradually added over 85minutes while maintaining reaction temperature of 72-74° C. After thisaddition was complete, the reaction mixture was held at 72° C. for 15minutes. A chase solution of 3.06 grams of sodium persulfate wasdissolved in 40 grams of deionized water and gradually added over 30minutes. When the feed was complete, the reaction mixture was held fortwenty minutes at 72-74° C. After the hold period, the reaction mixturewas cooled to room temperature. At 45° C. or below, 1.0 gram of a 30%solution of hydrogen peroxide was added slowly to reduce sulfite tozero. The resulting solution polymer had a solids content of roughly47.1%.

TABLE 1 Monomer mix recipe for polymer 1A (weights in grams) Example 1ADeionized water 0 Ethyl acrylate 459 Acrylic acid 1072

Example 1B Solution Synthesis Polymer 1B

A 5-liter round-bottom flask equipped with a paddle stirrer,thermocouple, nitrogen inlet, and reflux condenser was charged with 535grams of deionized water and heated to 92° C. At temperature, 35 gramsof 45% SBP solution was added, followed by a 15 minute hold whileallowing to cool to 86° C. A monomer mix of ethyl acrylate and acrylicacid was prepared according to the recipe shown in Table 2. After hold,and at temperature, the monomer mix and separate solutions of 15 gramsof sodium persulfate in 93 grams of deionized water and 33.4 grams of a45% solution of sodium hypophosphite were gradually added while allowingthe temperature to rise to a reaction temperature of 92° C. over 85minutes. After this addition was complete, the reaction mixture was heldat 92° C. for 20 minutes, then cooled to 75° C. A solution of 3.0 gramsof a 0.15% solution of ferrous sulfate was added to the reactionmixture. A solution of 1.3 grams of aqueous tert-butylhydroperoxide(70%) diluted with 10.0 grams of deionized water and a solution of 0.45grams of isoascorbic acid in 10.0 grams of deionized water were added asshots in one minute increments and held for twenty minutes. This stepwas repeated. After holding at temperature, the reaction was cooled toroom temperature and a blind dilution of deionized water was added below40° C. The resulting solution polymer had a solids content of roughly46.5%.

TABLE 2 Monomer mix recipe for polymer 1B (weights in grams) Example 1BDeionized water 265 Ethyl acrylate 450 Acrylic acid 1050

Example 1C Solution Synthesis Polymer 1C

A 5-liter round-bottom flask equipped with a paddle stirrer,thermocouple, nitrogen inlet, and reflux condenser was charged with amixture of 1070.6 grams of deionized water and heated to 72-74° C. Attemperature, 1.23 grams of Sodium Metabisulfite dissolved in 14.3 gramsof deionized water and 17.1 grams of 0.15% Ferrous Sulfate solution wasadded separately to the kettle followed by a 2 minute hold. A monomermix was prepared according to the recipe shown in Table 3. After hold,and at temperature, the monomer mix was gradually added over 120 minutesand a solution of 31.65 grams of Sodium Persulfate in 190 grams ofdeionized water was gradually added over 122 minutes and a solution ofSodium Metabisulfite (26.8 grams in 214 grams deionized water) wasgradually added over 115 minutes while maintaining reaction temperatureof 72-74° C. After this addition was complete the reaction mixture washeld at 72° C. for 15 minutes. A chase solution of 3.8 grams of SodiumPersulfate was dissolved in 20.1 grams of deionized water and graduallyadded over 30 minutes. When the feed was completed, the reaction mixturewas held for twenty minutes at 72-74° C. After the hold period, thereaction mixture was cooled to room temperature. At 45° C. or below, 1.0gram of a 30% solution of hydrogen peroxide was added slowly to reducethe sulfite level to zero. The resulting solution polymer had a solidscontent of roughly 47.1%.

TABLE 3 Monomer mix recipe for polymer 1C (weights in grams) Example 1CDeionized water 300 Acrylic acid 1712

Example 1D Solution Synthesis Polymer 1D

A 5-liter round-bottom flask was equipped with a paddle stirrer,thermocouple, nitrogen inlet, and reflux condenser, and was charged witha mixture of 679.0 grams deionized water and 102.7 grams of a 45%solution of sodium hypophosphite, then heated to 92-94° C. The monomermix was prepared according to the recipe shown below (Table 4). Separatesolutions of sodium persulfate, 19.7 grams, dissolved in 52.9 gramsdeionized water, and a 45% solution of sodium hypophosphite, 102.7 gramsin 52.9 grams deionized water, were prepared for the cofeed. The monomermix (Table 4) was gradually added over 120 minutes, sodium persulfatesolution cofeed added over 121 minutes and sodium hypophosphite solutioncofeed over 100 minutes, while maintaining a reaction temperature of92-94° C. After this addition was complete, the reaction mixture washeld at 92-94° C. for 15 minutes and then cooled to 85° C. A solution of1.54 grams sodium persulfate and 15.4 grams deionized water was preparedand added as a shot chase and held for 20 minutes. After this hold, thereaction was cooled to room temperature. A blind dilution was added asnecessary to achieve final solids content of roughly 50.0%.

TABLE 4 Monomer mix recipe for polymer 1D (weights in grams) Example 1DDeionized water 980 Acrylic acid 1966

Example 2 Preparation of Aqueous Curable Thermoset Compositions

Aqueous curable thermoset compositions were prepared using the followingpolycarboxy (co)polymers prepared in Example 1:

Ex. 1A 70 AA/30EA // 1.0% SMBS (Mw: 80,200; Mn: 18,700) Ex. 1B 70AA/30EA // 1.0% SHP (Mw: 48,000; Mn: 8,000) Ex. 1C 100 AA // 1.2% SMBS(Mw: 59,000; Mn: 11,000) Ex. 1D 100 AA // 2.1% SHP (Mw: 18,100; Mn:4,500)

The compositions were prepared by simple admixture, with stirring, ofthe components shown below in Table 5.

TABLE 5 Composition of aqueous curable thermoset samples 1-14(quantities in grams) Sample Polymer Polyol(s) PEG Accel. Amm. H₂O 1 100Ex. 1A 10.0 ethox. gly. 0 1.43 SHP 4.07 459.05 2 100 Ex. 1A 4.42 ethox.gly. 8.46 6.44 SHP 6.93 359.50 3 100 Ex. 1C 4.99 ethox. gly. 8.69 9.35SHP 3.54 474.19 4 100 Ex. 1C 5.35 ethox. gly. 8.05 5.19 SHP 3.50 461.615 100 Ex. 1A 3.44 ethox. gly./2.20 TEOA 9.40 1.43 SHP 4.11 440.46 6 100Ex. 1C 4.99 ethox. gly./3.19 TEOA 10.14 2.08 SHP 1.08 483.28 7 100 Ex.1A 3.93 ethox. gly./1.10 TEOA 0.00 1.43 SHP 2.41 419.30 8 100 Ex. 1C5.71 ethox. gly./1.60 TEOA 0.00 2.08 SHP 0.00 455.86 9 100 Ex. 1A 12.95glycerol 0.00 6.41 SHP 0.00 486.80 10 100 Ex. 1C 14.30 glycerol 0.009.36 SHP 3.74 562.31 11 100 Ex. 1B 10.4 ethox. gly. 0.00 1.43 SHP 1.40365.99 12 100 Ex. 1D 15.0 ethox. gly. 0.00 2.00 SHP 0.00 435.33 13 100comp. 1 18.02 glycerol 0.00 8.92 SHP 4.90 548.32 14 100 comp. 2 17.58TEOA 0.00 4.26 SHP 0.00 624.45 All formulations contain Triton X-114 at<0.1% to wet the polyester substrate. Ethox. gly. is Chemal ™ G-35/90(PCC Chemax, Inc., Piedmont, SC, USA), an ethoxylated glycerol of 2200molecular weight (100% active ingredient). PEG = polyethylene glycol at20,000 molecular weight (30% active ingredient). Amm. = concentratedammonium hydroxide solution, 28%. TEOA is triethanolamine (99% activeingredient). Formulation 14 contains 4.84 gms. concentrated sulfuricacid to adjust to pH = 3.0. SHP is sodium hypophosphite, added as 45%solution by weight in water. Comparative 1 is Acumer ™ 9932 polyacrylicacid (48.3% wt. solids) (Rohm and Haas Company, Philadelphia, USA).Comparative 2 is QRXP-1676 polyacrylic acid (53.1% wt. solids) (Rohm andHaas Company, Philadelphia, USA).

Examples 3 Treatment of Polyester Mat and Tensile Testing of TreatedSubstrate Test Methods—Mat Preparation:

Commercial spunbound needle-punched polyester mat (150 g/m²;non-treated) was cut into 38 cm×30 cm sheets. A sheet was dip coated ineach test sample binder composition at 10% bath solids (by weight) andthen run through a roll padder with roll pressures of 40 psi to obtain abinder add-on weight of 20%+/−1% (dry binder weight as a percentage ofsubstrate weight). The coated substrate was then immediately cured byheating at 205° C. for 3 minutes in a Mathis Oven that is vented orequipped with a devolatilizer.

Tensile Strength, Elongation and Width Retention

An Instron 4201 tensile tester equipped with a 1 kN load cell and anoven chamber encasing the jaws with temperature range capability of −100to 400° F. (−73° C. to 204° C.) was used for both room temperaturetensile strength (RT TS) and elongation (RT elong.), and hightemperature tensile strength (hot TS) and width retention (hot width).

For RT tensile strength and RT elongation, a cured sheet was cut into 4cm×25 cm strips. Strips were tested by placing them in the jaws of thetensile tester and pulled apart, at room temperature (˜23° C.), at acrosshead speed of 8 inches/minute (approx. 20 cm/min) with a 15 cm gap.Tensile strengths were recorded as the peak force measured duringparting (Table 6). The maximum percent elongation was also recorded. Thedata reported are averages of 4 test strips for each binder compositiontested.

For high temperature tensile strength and width retention a cured sheetwas cut into 2.5 cm×30 cm strips. The oven chamber of the tensile testerwas pre-heated to 375° F. (190° C.) prior to testing. Once pre-heated,the strips were placed in the jaws and the oven chamber closed andequilibrated back to 375° F. The samples were then pulled apart at acrosshead speed of 20 cm/minute with a 15 cm gap. Hot Tensile Strengthwas measured at 20% elongation. Hot Width Retention was calculated bymeasuring the width of the test strip at the narrow point and dividingthis by the initial width, expressed as a percentage. Hot WidthRetention is a measure of the thermal dimensional stability of thesubstrate.

TABLE 6 Hot and room temperature tensile test and elongation resultsSample Hot TS (N) Hot Width (%) RT TS (N) RT Elong. (%) 1 145 83 399 392 123 78 374 45 3 124 78 328 40 4 120 81 320 41 5 131 77 342 42 6 111 75351 37 7 135 81 383 30 8 140 81 338 42 9 172 81 378 21 10 173 82 311 2011 150 95 379 30 12 130 94 409 38 13 157 77 281 21 14 155 79 301 22 15151 83 526 43Sample 15 is a 90/10 blend of styrene acrylic emulsion polymer andmelamine formaldehyde resin.

In Table 6, samples 13, 14 and 15 represent control samples. Sample 15represents an optimized system for the previous generation technologywhich uses the undesirable melamine-formaldehyde crosslinking systems asa component of the thermoset binder. Sample 15 has very good tensilestrength properties (hot TS and room temperature TS), as well as goodroom temperature elongation and acceptable hot width retention. Indeed,in this respect, the industry is struggling to replace this technology.Comparative 2 in sample 14 is a polyacrylic acid binder and usestriethanolamine as the crosslinker, and Comparative 1 in sample 13 is acommercial polyacrylic acid thermosetting binder, Acumer™ 9932, which iscrosslinked with glycerol. The data for samples 13 and 14 in Table 6show that this next generation formaldehyde-free technology iscomparatively deficient in flexibility and room temperature tensilestrength.

Samples 9 and 10 also use glycerol as the crosslinking polyol, and bothsamples have similarly poor flexibility as shown by the low roomtemperature elongation.

Inventive sample 1 shows that a good balance of properties can beachieved when ethoxylated glycerol is used as the crosslinking polyol,including good room temperature elongation and tensile strength. Othersamples in the series illustrate that even better flexibility can beachieved using ethoxylated glycerol as the polyol, for example insamples 2, 3 and 4, which further comprise polyethylene glycol (PEG).Moreover, the balance of properties can be refined to optimize for aspecific end-use application, as shown, for example by samples 5-8.

1. A curable aqueous composition comprising (a) at least one polycarboxypolymer or copolymer comprising at least two carboxylic acid groups,anhydride groups, or salts thereof; (b) at least one glycerol derivativehaving weight average molecular weight greater than 1000 and comprisingat least three hydroxyl groups, the said glycerol derivative chosen fromthe group consisting of ethoxylated and propoxylated glycerol of formulaI

in which u, v, w, x, y, and z independently of one another are 0-50,with the proviso that the total sum of u, v, w, x, y, and z provides aweight average molecular weight of the glycerol derivative greater than1000; wherein the ratio of the number of equivalents of said carboxylicacid groups, anhydride groups, or salts thereof to the number ofequivalents of said hydroxyl groups is from 1/0.001 to 1/1.
 2. Thecurable composition of claim 1 in which (a) consists of at least oneaddition copolymer of (meth)acrylic acid with one or more monomersselected from the group consisting of C₁-C₁₂ alkyl (meth)acrylates,C₁-C₁₂ hydroxyalkyl (meth)acrylates, vinyl esters of C₂-C₁₂ carboxylicacids, butadiene, vinyl acetate, alkyl maleates and alkyl fumarates. 3.The curable composition of claim 1 further comprising at least onepolyether compound of the general formula HO—(CR₂—CR₂—O)_(n)—H, in whichR independently at each occurrence is H or C₁₋₄ alkyl, and n is between5-100,000.
 4. The curable composition of claim 1 further comprising atleast one phosphorous-containing compound.
 5. The curable composition ofclaim 1 further comprising at least one low molecular weight polybasiccarboxylic acid with molecular weight of 1000 or less, including citricacid, adipic acid, glutaric acid, malic acid, ascorbic acid, asparticacid, crotonic acid, itaconic acid, tartaric acid, maleic acid, fumaricacid, succinic acid, t-cinnamic acid and mixtures thereof.
 6. Thecurable composition of claim 1 further comprising at least one emulsionpolymer including, as polymerized units, at least one ethylenicallyunsaturated nonionic acrylic monomer.
 7. The curable aqueous compositionof claim 1 further comprising one or more polyols selected from thegroup consisting of glycerol, ethyleneglycol, diethyleneglycol,triethyleneglycol, hexanediol, trimethylolpropane, pentaerythritol,sorbitol, sucrose, glucose, triethanolamine and diethanolamine at alevel of from 0 to 10% by weight on total formulation solids.
 8. Thecurable composition of claim 1, wherein the polycarboxy polymer (a) ispolyacrylic acid.
 9. A method for treating fibrous, non-woven orcomposite substrates comprising: forming a curable aqueous compositioncomprising admixing with water or one or more aqueous solvent (a) atleast one polycarboxy polymer or copolymer comprising at least twocarboxylic acid groups, anhydride groups, or salts thereof; (b) at leastone glycerol derivative having weight average molecular weight greaterthan 1000 and comprising at least three hydroxyl groups, chosen from thegroup consisting of ethoxylated and propoxylated glycerol of formula I

in which u, v, w, x, y, and z independently of one another are 0-50,with the proviso that the total sum of u, v, w, x, y, and z provides aweight average molecular weight of the glycerol derivative greater than1000; wherein the ratio of the number of equivalents of said carboxylicacid groups, anhydride groups, or salts thereof to the number ofequivalents of said hydroxyl groups is from 1/0.001 to 1/1; contactingsaid substrate with said curable aqueous composition or, alternatively,applying said curable aqueous composition to said substrate; and heatingsaid curable aqueous composition at a temperature of from 100° C. to400° C.
 10. A fibrous article, non-woven article or composite substrateprepared by the method as claimed in claim 9.